In order to save energy and avoid misoperations, mobile or wearable devices are generally set with a screen locking function, and a lock screen may be unlocked with or without a password. When a screen with a password is to be unlocked, a user needs to memorize some special passwords, patterns, actions, or the like. Although security can be ensured, a case in which the user forgets those special passwords, patterns, actions, or the like occurs easily, which brings inconvenience to the user. Certainly, in addition to the foregoing scenario of unlocking the screen, the foregoing problem also exists in other scenarios in which passwords need to be input for further operations.
By using digital watermark technologies, some identifier information (that is, the digital watermark) may be directly embedded in a digital carrier without affecting using of the original carrier, and the identifier information is not detected and modified easily. The digital watermark technologies are applied to many aspects, such as copyright protection, anti-counterfeiting, authentication, and information hiding. If the digital watermark technologies can be used to securely and covertly help the user input a password, or the like, to obtain corresponding authorization, the foregoing problem that authentication cannot be performed because the user forgets the password may be solved, thereby improving user experience.